Triple-Redundant Air Data System Using Dual MFPs
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Solution Overview
Problem
Modern aircraft air data systems face challenges in achieving accurate air data parameter determination during sideslip conditions, particularly in Reduced Vertical Separation Minimum (RVSM) spaces, due to the complexity and cost associated with multiple pneumatic or electronic multi-function probes (MFPs, which also increase weight and space requirements.
Innovation Solution
An air data system architecture utilizing two dual-channel multi-function probes (MFPs) and two static pressure sensors, where the static pressure sensors provide static pressure data for sideslip compensation, reducing the need for additional MFPs and enhancing redundancy, independence, and dissimilarity, thereby decreasing cost, weight, and space while increasing system reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple pneumatic or electronic multi-function probes (MFPs) are used to achieve accurate air data parameter determination during sideslip conditions, then measurement precision is improved, but device complexity, weight, and cost increase
Solution Approach 1:
The system divides the air data measurement function into two independent sources: two MFPs for dynamic pressure measurement and multiple static pressure sensors for static pressure measurement. This segmentation allows static pressure to be measured at multiple locations without requiring multiple complete MFP assemblies, reducing overall system complexity while maintaining measurement precision through sideslip compensation.
Solution Approach 2:
The MFPs are designed with multi-functionality, serving both as dynamic pressure sensors and as sources of static pressure data for sideslip compensation. The static pressure sensors are integrated into the system to provide additional measurement capabilities. This multi-functionality reduces the need for separate dedicated components, thereby reducing device complexity while maintaining accuracy.
2Measurement precision
If multiple pneumatic or electronic multi-function probes (MFPs) are used to achieve accurate air data parameter determination during sideslip conditions, then measurement precision is improved, but weight increases
Solution Approach 1:
The system segments the measurement functions by using two MFPs for dynamic pressure and adding static pressure sensors for static pressure measurement. This avoids the weight penalty of installing three or more complete MFP assemblies, as static pressure sensors are significantly lighter than full MFP units, thereby reducing overall system weight while maintaining measurement precision.
Solution Approach 2:
Instead of copying complete MFP assemblies to provide redundant static pressure measurements, the system uses simpler static pressure sensors that replicate the static pressure measurement function. This copying approach provides the necessary measurement redundancy for sideslip compensation without the excessive weight of multiple full MFP units.
3Measurement precision
If multiple pneumatic or electronic multi-function probes (MFPs) are used to achieve accurate air data parameter determination during sideslip conditions, then measurement precision is improved, but cost increases
Solution Approach 1:
The system segments the measurement functions by using two MFPs for dynamic pressure and adding static pressure sensors for static pressure measurement. This segmentation reduces cost by avoiding the need for three or more expensive MFP assemblies, as static pressure sensors are significantly cheaper components, thereby reducing overall system cost while maintaining measurement precision.
Solution Approach 2:
The system replaces expensive MFP units with cheaper static pressure sensors for the specific function of static pressure measurement and sideslip compensation. This substitution uses lower-cost components to perform the same measurement function, reducing overall system cost while maintaining the required measurement precision.
4Reliability
If three, four, or more electronic MFPs are used to provide redundant air data parameters from independent sources, then reliability is improved, but device complexity, weight, and cost increase
Solution Approach 1:
The system achieves redundancy by segmenting the measurement sources into two independent MFPs and multiple static pressure sensors. This provides three independent air data systems without requiring three or more complete MFP assemblies, reducing device complexity while maintaining the required level of redundancy and reliability for certification.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration forms three independent air data systems, reducing the likelihood of common mode failures and enhancing system reliability by using static pressure sensors instead of additional MFPs, thereby decreasing the overall weight, space, and cost of air data system components while maintaining high availability of air data parameters.
Implementation Method 1
a first plurality of pressure sensing ports for sensing pressure of an oncoming airflow about an aircraft exterior
Implementation Method 2
a first static pressure sensor configured to sense static pressure of the oncoming airflow about the aircraft exterior
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A first air data system for providing first aircraft air data parameter outputs is formed by a first electronics channel (28) of a first multi-function probe (MFP) (12A) that is electrically coupled with a first static pressure sensor. A second air data system for providing second aircraft air data parameter outputs is formed by a first electronics channel (30) of a second MFP (12B) that is electrically coupled with a second static pressure sensor. A third air data system for providing third aircraft air data parameter outputs is formed by a second electronics channel (30) of the first MFP (12A) that is electrically coupled with a second electronics channel (30) of the first MFP (12A).